Rob - take care when considering inductor gauge change. Although there may be no actual / functional differences, the fact remains that the coil resistance (as designed) is an integral part of the circuitry. Your change will change the circuit dynamics, and since Jim tuned those dynamics to a nub, I suspect you will not improve them. In fact, the differences may be small enough not to matter. But then consider what value are you getting? Note also that Thiel (ERSE - special) coil wire quality might be impossible to replicate in today's supply chain.
A real potential advantage is going from wire to foil, which acts more like a perfect inductor. In that case the Effective Series Resistance is quite different and may have even more impact on the circuit dynamics. In such case, you can re-establish the proper value / performance be inserting a series resistor after the coil, but its thermal dissipation will be considerably worse than the coil.
You might consider re-mounting the existing coil on stand-offs for more effective and even thermal dissipation than standard Thiel glue-down. That's where I have landed in my explorations. Just sharing a perspective.